The correct option is A 0
As the maximum value of sinx is 1, for the given sum to be 2, both sin2x and sin4x must be 1.
∴2x=(4n+1)π2 (n∈Z)
But then, 4x=(4n+1)π⟹sin4x=0
Therefore, there is no solution as it is not possible for sin2x and sin4x to be 1 at the same time for any x.